Answer:
A) a vertical line does not represent a function.
Step-by-step explanation:
For a relation to be a function for each value of 
there must be only one value of 
. In other words a function is one in which each value in the domain set corresponds to only one value in the range set.
Let us check for this condition in the give choices:
A) a vertical line
A vertical line is given as 
which meas it is parallel to y-axis and has infinite number of values for a single value.
So, its Not a function
B) 
For the given equation, on plugging in some value will give a single value.
So, its a Function
C) a horizontal line
A horizontal line is given as 
which meas it is parallel to x-axis and has infinite number of values giving a single value.
So, its a Function
D) {(1, 7), (3,7), (5, 7), (7,7)}
For the given set for different valuesthere is only one value.
So, its a Function
If you mean unit rate you find it by dividing the top number by the bottom number to fin the singular number or unit rate.
Hahah what you learning...............
The driver's tip was $1.45 because the trip cost $8.55 (2.25+1.5+1.5+1.5+1.5+ 0.3) and Eric gave the driver $10 so to find how much the driver got tipped, you need to subtract 8.55 from 10 so $10 - $ 8.55 = $1.45
